I've recently bought the UD2.0 book and I am currently planning my schedule for food & workouts.

I'm having issues planning the carb refeed without reaching the 50g fructose / 100g sucrose... also I have already posted this on the facebook group, maybe I could have more help here.

I was planning to eat corn flakes with skimmed milk but even 500g + 1L of milk is already more sugar than recommended by Lyle, I don't even know how I could include burger,pizza or donut with those limitations..

Anyway, my main question is : what carb source could I eat that contains absolutely no sucrose/fructose ?
On my facebook post cream of rice has been mentioned, I've looked at it at groceries it does not look very appetizing :/ I am not sure I can eat 900-1000g of carbs with something looking like floor melted in cold water. And I don't want to mess with the diet by taking too many sugar.

Honestly, you kind of have to just suck it up and eat the bland cardboard tasting carbs if you want the best results. The refeed is far from a "cheat day." I actually feel it's much more restrictive than the 2 following days. I'm not quite sure how anyone would fit pizza or donuts on given the extremely low amount of fat you're allowed to have. Honestly, rice, bread, pasta, and maybe a couple sweet potatoes with just a bit of junk is the way you need to go if you want the best results. Throw a donut in on the power workout day if you must.

So basically pasta, raw bagels, cream of rice every of these food is ok ?
I also found candies (smarties) made only of dextrose and maltodextrose, is it ok ? Or the elevated GI will mess it ? (but as I am looking at it even pasta, bagels or cream of Rice have high gi)

I can't speak for Lyle, but I don't think the GI matters too much. I think if there's a priority list for the refeed it goes:
1) <50g fat
2) Sucrose/Fructose below 100g/50g respectively
3) Carb timing (I believe it's around 1/7 of your carb allotment every 2 hours during your waking hours starting after the refeed)
4) Any other concerns you might have (i.e. glycemic load, fiber content, etc)

From experience, you'll want to have a fair amount of high GI carbs or you'll feel extremely bloated all day and possibly for the next couple days. Try to limit your fiber intake as much as possible as well. I wouldn't worry about the glycemic load too much. I've read a lot of different logs where people use the smarties or other dextrose-based candies for their carb allotment immediately post workout.

I ran 2 8 week cycles last year, and I got pretty good results. Looking to start up again soon actually. My main tips for the carb load are keep fat low, don't consume an insane amount of sugar, and find foods that will fit your carb load that you actually enjoy to reward yourself for all the hard work you put in over the week. I never even worried too much about Sucrose/fructose amounts when I did the diet, and I still got great results. Would I have gotten better results if I did? Maybe but the diet still works either way.

A fun thing I always did during my UD2 cycles was to hit the grocery store immediately before my tension workout and buy the food for my carb load (I never kept any carbs in my apartment during the week so I wouldn't be tempted to cheat). I would look at the nutrition labels and try to find items that had <2.5g fat/50g carbs (I was doing 1000g carbs during the load and eating <50g fat). To me, if it met that ratio it was fair game. Obviously, I would keep the sucrose/fructose thing in mind (i.e. I didn't go buy 2kg of Skittles), but I didn't let it define the load either.

If you can do your entire refeed on smarties, you are not human. Not sure if anything bad would happen but I definitely couldn't recommend it for sanity's sake. But the first 150-200g, sure. Lyle recommends a dextrose shake with some whey, and smarties are dextrose so I don't see a problem with that.